The invention relates to a method for operating a speech recognition arrangement. In particular, the invention relates to a method as recited in the preamble of Claim 1. At present, various appliances are becoming voice-controlled. The operative outputting may imply executing a command, asking for further speech input, or having another result that is appropriate for the appliance in question.
Now, many present-day dedicated speech recognition circuits use only a small active vocabulary, which smallness feature brings about the advantage of fast and accurate recognition. An associated disadvantage is however that only commands and similar items within a limited set thereof can ever be recognized. Reloading of a different vocabulary into the arrangement is a relatively slow and tedious process that, even if successful, would slow down an interactive recognition process appreciably, in particular, because the presentation of a next speech item would have to wait until recognition of all preceding speech items were accomplished.
The present inventors have recognized that recording of the sound as received is often not the bottleneck, and that a hierarchical recognition procedure would allow to combine a relatively large overall vocabulary with the possibility for allowing uninterrupted continuous speech inputting. Moreover, they have found that users may well be saying there right words, but are prone to present an incorrect sequence of speech items. In fact, irrelevant items may be inserted, the sequence of the words may be inverted with respect to the correct one, and so on. In consequence, the inventors have come up with the idea that the recognizing of certain speech items might be delayed or abandoned, in favor of the recognizing of other speech items as received, to so improve flexibility by means of simple and inexpensive measures.
The inventors have also recognized that the calling up of a next speech item may be an order of magnitude faster than the calling up of a next partial vocabulary, in as much as such vocabulary may contain a much larger number of items-for-recognition.